WITH his bandanna and long dark hair, wearing something that looks like a flak jacket, swarthy Gottfried Helnwein could be a guerrilla or a pirate-revolutionary.
But the rock 'n' roll lifestyle and 17th-Century castle in Co Tipperary adorned with huge canvases tell a different story. He's an artist of serious international reputation, veteran of many controversies, who counts Sean Penn, Marilyn Manson, Norman Mailer and, once, Marlene Dietrich among his friends.

Yet he says the only achievement of which he is really proud is the way he brought up his four children. He gives his ideal job as "member of the Rolling Stones".

Now 58, Helnwein has exhibited throughout the world since the early Seventies, often attended by public outrage and sometimes violent responses. He is collected by Nicolas Cage, Billy Wilder and Andrew Lloyd Webber, has created costume and stage sets for opera and theatre, and appeared on the cover of a Scorpions album.

In the Venn diagram between celebrity and the contemporary art world - where Madonna sparks a buying frenzy by turning up at the San Francisco art fair and Ben Kingsley opens exhibitions by Irish artist Patrick Morrison, one of Helnwein's proteges - he is entirely at home.Which is not to suggest that he isn't serious about what he does, or passionate in his leftist social and political beliefs. Part of his success is that the core of his work has remained unchanged since the beginning: his signature massive photo-realistic images of children.

He paints and photographs children on the cusp of an adult intelligence. Most have their eyes closed, and might be sleeping or dead. Sometimes he cakes them in a ghostly white, bandages them poignantly, or twists their features with hideous surgical instruments. The message is clear and powerful - innocence defiled - but the medium is often just as troubling.Then there is the recurring theme of Nazism - SS uniforms, swastikas, sometimes recognisable faces from Hitler's regime - often used in provocative connection with a childish figure.Some of his work is beautiful, some frightening, some deliberately grotesque. All carries with it the kind of murky atmosphere that Carol Reed created for The Third Man, a film set in the post-war Vienna - where Helnwein grew up.

The result is disturbing. Even the beautiful work is queer. Small wonder, perhaps. Helnwein was born in Vienna three years after World War Two ended, a dark and dismal place. He draws parallels with Ireland at the time - the power of the Catholic Church, the poverty - but of course Austria was carrying its own particular burden of post-war guilt and secrecy.Helnwein remembers it with a nightmarish clarity: "The Nazis were still there. This horrible feeling of death was everywhere."

A sensitive child, born into a "lower middle-class" family, Helnwein was aware very early that there was a strangeness in the air. "I realised everybody was lying all the time. There was this total inability to talk about the war. But I knew there was something. I saw the pictures of my father and my grandfather in uniform, and wanted to know what happened, but they would tell me nothing."When he did find out, "It was like a shock." So he decided, "This is not my country. Many people of my generation felt that about Germany and Austria. We didn't want to be part of it. We didn't want their culture, their traditions, anything."

However, still a child, he couldn't yet turn revulsion into action. He was trapped.The only ray of light into the shadowlands of Vienna then was American culture, brought by the GIs sharing control of the city with the Russians and British. To the post-war kids, Donald Duck was an icon and an inspiration. Helnwein came across him at the age of four: "Opening this comic book was like stepping into the real world where I wanted to be, like leaving a black and white silent film."Elvis was an even greater revelation. "It was a beauty like I had never seen. I thought, how can anyone be this beautiful? People in Austria were all ugly."

Then came the Sixties, coinciding with Helnwein's adolescence. Although he always liked to draw, and demonstrated considerable talent, Helnwein had no thought of becoming an artist. "The only thing I wanted was a revolution. I thought everything had to be destroyed."It was his hatred of authority that sent him to Vienna's Academy of Fine Arts, where he realised art was a way out of the uniformity and conformity of the time.

His early exhibitions, where all his prodigious talent was brought to bear on an uncompromising, almost surgical investigation into Austria's past, stirred up a vicious public reaction.One of those early paintings caught the attention of the woman who is still his wife and manager. Renate had been working as a nurse in a psychiatric hospital, ministering to the victims of the inhumane treatments then considered appropriate for disturbed children. When she came across an image of a wounded child created by Helnwein, it spoke to her in a special way. She travelled to Vienna to meet the artist, and has been with him ever since.

The couple married in 1982, by which time they had three children. They moved to Germany, then to America, where Helnwein realised that despite the freedom, he was at heart a European. So Helnwein's "gypsy tribe", now grown to four children, came looking for a base, and found Ireland. "It was intuition. I had never been here before, and didn't know anything about it."They arrived one rainy Christmas nine years ago and bought the beautiful 17th-Century Tipperary castle, and settled down to create a sanctuary. They now divide their time between it and a studio in LA. Helnwein takes huge delight in the children, particularly the fact that all are artists: Cyril is a photographer; Mercedes, a writer and visual artist; Ali, a musician; and Amadeus, just started at UCD, writes poetry.

Last summer the castle was magicked into a kind of Edgar Allen Poe fairy tale for Marilyn Manson's wedding to Dita Von Teese. "I really enjoyed it. It was so beautiful. Everything was only about beauty, in a really innocent sense."Helnwein's connection with Manson is a deep one. "When I met him, it was like I knew him forever. He has something that's almost died out today - it's fashion as art. His life is like theatre."That brings him to Marlene Dietrich, who he and Renate knew well for the last 10 years of her life. "I think she was one of the last people who was really good with her clothes and the way she looked. It was really artificial, in a good way."

His admiration of Dietrich is profound. "She was brave. The Reich wanted her to come back to Germany, they would have offered her anything. And she said, 'Ach, bullshit. I don't understand anything about politics, but I saw how they treated my friends the Jews. What do you have to understand?' She had integrity, knew to trust her heart and not the experts."Again he comes back to the war, and the evils of the modern world, of which he ranks abuse of children worst of all.

These are things he cannot get over, cannot be blind to. Hence the need to remind people constantly through his art. "Just reminding is not enough," he adds. "They have to understand what it is you are reminding them of."

He also understands the need to promote himself and his work. "It's the price you pay for independence," he says simply. "I'm not dependent on anything - not on the art market, not on a gallery."For a man who refuses not to see, freedom is what matters. To be able to say, "I never have to make a compromise, or do things that I think might be wrong," means everything.

Gottfried Helnwein, Modern Sleep, is at the Fenton Gallery, Cork, until October 7